Italian children with Hashimoto’s thyroiditis are more likely to develop thyroid nodules over 4 years than children without the condition, but the incidence of thyroid cancer remained low, according to findings from a retrospective study.

Giorgio Radetti

“The prevalence of thyroid nodularity is increased in children with autoimmune thyroiditis, but is not associated with an increase in thyroid cancer,” Giorgio Radetti, MD, a specialist in pediatric endocrinology at Marienklinik in Bolzano, Italy, told Endocrine Today. “Children with autoimmune thyroiditis are not at risk of developing thyroid cancer.”

Radetti and colleagues analyzed data from 904 children and adolescents diagnosed with Hashimoto’s thyroiditis between December 2003 and July 2016 (709 girls), followed at nine Italian pediatric endocrinology centers for a median of 4.5 years. Researchers evaluated yearly levels of thyroxine, thyroid-stimulating hormone, thyroid peroxidase antibody (TPOAb), thyroglobulin antibodies (TGAb) and data from thyroid ultrasounds.

Within the cohort, five patients had hyperthyroidism, 58 had subclinical hypothyroidism, 144 had hypothyroidism and 697 were euthyroid at diagnosis.

At diagnosis, thyroid ultrasound revealed the presence of thyroid nodules in 77 children (8.52%), with thyroid cancer already present in three children (0.33%). At last visit, researchers observed an increase in frequency, with 174 children with thyroid nodules (19.2%) and thyroid cancer present in 10 children (5.7%). The annual incidence rate of thyroid nodularity over 10 years was 3.5%, according to researchers. The probability of children with Hashimoto’s thyroiditis having a nodule was 9.3% at diagnosis, increasing to 43.9% at 10 years.

Researchers found that the incidence of new thyroid nodules was positively influenced by the severity of hypoechogenicity at ultrasound (P < .001), serum TPOAb (P < .05) and treatment with levothyroxine (P < .05). Researchers also observed a positive correlation between TPOAb level and development of thyroid cancer (P < .01).

“Our findings clearly show that [Hashimoto’s thyroiditis] influences the development of thyroid nodular pathology, but not of cancer” the researchers wrote. “These findings are comparable to those reported in adult subjects.” – by Regina Schaffer